The present invention relates to electrical programmer/timers for appliances and particularly for household appliances such as washing machines, dishwashers and clothes dryers having user selected program intervals. Appliances of this type typically have a knob or dial rotated by the user for selection of the length of the appliance service program. The user rotates the dial to the selected dial position or mark for positioning a rotatable program cam operative to be advanced or rotated by a suitable timing mechanism such as a motorized speed reducer or periodically advanced pawl driving a toothed ratchet connected to the program cam and indexing the cam with each stroke of the pawl for time-out of the selected program interval. The program cam is typically contacted by a plurality of cam followers positioned thereabout for providing a desired sequence of operation to electrical function switches connected to each of the cam followers. The switches typically provide for the desired individual appliance functions such as controlling an electric water inlet valve, a water drain pump or drain valve, or an agitation and spin motor.
Programmer/timers of the above-described type are typically driven by a small subfractional horsepower synchronous timing motor which is connected to the appliance power line connector via a line switch. In some household appliance designs, it has been desired to provide actuation of the appliance line power switch by providing an axial movement to the program knob or dial for actuation of the line switch. Where space is at a premium for packaging the programmer/timer in the appliance control panel housing, the size of the program cam drum is limited, which in turn limits the number and size of cam actuated function or program switches that can be disposed about the cam drum for actuation thereby. It has therefore been desired to integrate the line function switch with the switches actuated by the program cam followers to conserve space and reduce manufacturing cost.
Where the appliance line power switch is combined with cam actuated switching functions, it has been found difficult to provide for separate user-actuation of the line power switch to retain user control of the appliance, and yet also provide for continuing power to the timing motor for advancing the cam to a desired position for restart after all other appliance functions have been disconnected by the power line switch.
It is known to provide an appliance programmer/timer having a rotary program cam for actuating a plurality of function switches wherein the line switch is combined with a program switch and the line switch is actuated by axial movement of the knob shaft for moving a slider to actuate the line switch. An example of such is described in U.S. Pat. No. 3,431,372 in the name of G. Obermann and in U.S. Pat. No. 4,497,985 in the name of Courter etal. However, the aforementioned programmer/timers having a combined program and line function switch do not provide for maintaining power to the timing motor irrespective of the position of the line switch actuator for certain positions of the program cam.
Thus, it has been desired to find a way or means of providing an appliance line switch combined with a cam operated program switch in a programmer/timer having rotary cam drum for actuating program function switches and to maintain power to the timing motor for certain positions of the program cam drum when the line switch is manually opened with the cam drum in such position.